Ejector detent



March 1950 c. G. SWEBILIUS I 2,500,139

ELECTOR DETENT Filed Sept. 11, 1946 inimum.-

B51 15; fiwebilius A w MM 1 2mm Patented Mar. 7, 1950 UNITED STATES PATENT OFFKIE EJECTOR DETENT Carl G. Swebilius, Hamden, Conn. Application September 11, 1946, SerialNo. 696,280

3 Claims. 1 V My invention relates to improvements in automatic guns, more particularly to a simplified empty case ejector and live round positioner, and it comprises a spring loaded ejector detent retained in the bolt assembly of the weapon.

While my invention may be adapted for use with other automatic weapons, in the. present instance it is shown applied to the Browning machine gun, type M2. In automatic guns of this type, as the bolt'recoils, a cartridge is drawn from the cartridge belt by the extractor and the empty case is. withdrawn from the chamber of the T slot in the face of the bolt; As the bolt moves to the rear, the extractor cam forces-the extractor down, causing the cartridge to enter the T slot above the empty case. Upon counter-recoil, the cartridge is forced farther down in the T slot, and the ejector, pivotally mounted on the extractor, engages the groove of the empty case to expel it from the gun. The ejector also cooperates with an extractor stop pin to limit the travel of the extractor by acting as: a. lower stop, positioning the cartridge vertically in the T slot so that it will enter the chamber.

Thus, we see that the two functions performed by the ejector are (a) to eject the empty case from the gun, and, (b) the final positioning of the in-feeding live cartridge in the T slot for entrance into the chamber. The latter is its chief function, andit has been found that the pivoted ejector frequently fails to carry out this function under the high rate of speed of the type M2 gun, 750 to 850 shots per minute, causing jamming, and other troubles such as the failure of the gun to fire after a few rounds because the end claw" of the ejector has been broken. or worn oil.

My invention provides for the. elimination. of the. trouble making ejector. I have invented. a spring. loaded stop member to be positioned in the. bottom of the T slot. My device acts; as a stop to position the in-feeding cartridge in. the

bolt face after the new round has forced the empty case past the spring arms of the device. The extractor, being relieved of the task of cartying the old ejector, is also able to carry out its own function more efficiently.

A principal object of my invention is to provide an ejector detent for an automatic gun which will permit the elimination of the present ejector.

An important object of my invention is to provide a spring detent for insertion in the T slot of an automatic gun which will cooperate with the extractor in ejecting the empty case, and which will, also provide final positioning of'the indeed.- ing round for entrance into the gun chamber.

' Another important object of my invention is to increase the efliciency of the: extractor of. an automatic gun by removing the ejector now carried by said extractor.

A further object of my invention is to proridev a spring loaded stop member which may be mounted at the bottom of the T slot of an automatic: gun to arrest the travel of a new round through said T slot and position the said new round vertically so that it will. enter the chamber of the gun.

A still further object of my invention is to pro.- vide an ejector detent for automatic guns which will be easy to manufacture, simple to install, and efficient in. operation.

Other objects and advantages, of my invention will become. apparent to one skilled in the art in the following specification, and accompanying drawings, forming part of the specification, wherein like numerals are used to designate like parts throughoutthe specification and drawings.

In these drawings:

Figure l is a fragmentary side elevational view of the standard bolt assembly of an automatic gun embodying my invention,

Figure-2. is a front elev-ational view of the same, the extractor being omitted,

Figure 3. is a bottom view of the same partly in section, with the bottom of. the ejector detent housing partly removed and the extractor omitted,

Figure 4. is a perspective view of detent, and,

Figurefi i a fragmentary perspective view of a standard bolt assembly embodying my invention, showing the ejector detent functioning to position the round for entrance into the gun chamber.

Referring now'to the drawings the numeral l0 identifiesgenerally the standard bolt assembly of an M2 gun. The bolt I 0 is arranged at one end with a vertical notch or slot ll, generally referred to in the art, and hereafter in the specification, as the T slot, provided with opposed flange members l2 and I3, the said flange members I2 and I3 being adapted to engage the groove of a cartridge [4 to retain the base of said cartridge l4 within the said T slot II while permitting passage of the body of said cartridge therebetween so that it may enter into and be withdrawn from the chamber of the gun (not shown) by the reciprocating movement of the gun bolt during recoil and counter-recoil of the the ejector gun. Since the empty cartridge case within the gun chamber has been expanded by the force of the explosion and a possibility exists of tearing the case if withdrawal is too rapid, the sides of the flange members l2 and I3 are beveled, as at l5, to permit the bolt to move away from the gun barrel in a gradual manner.

In the present art, the members l2 and I3 extend downward to the bottom of the bolt H), but when said bolt is adapted for use with my invention the bolt is cut away near the bottom of and immediately below the opposed flanges 16 on either side of said bolt to provide a recess 11 adjacent the T slot l l, of a size and for such purpose as will become apparent tical flange members 12 and 13 are accordingly in the course of this specification. The T slot H' and the vershortened so that their lower extremities will be adjacent the top of said recess 11.

The bolt is also provided with an extractor l8, mounted thereon for pivotal movement-relative to said bolt and adapted to engage the cartridge M to draw'it from the cartridge belt to the top of the T slot II where said extractor I8 is forced downward by an extractor cam (not shown) during the counter-recoil of the gun, causing the cartridge to enter the T slot of said bolt.

My invention comprises a generally U-shaped ejector detent l9 formed of flat Spring steel, the free ends forming fingers and 2| on the opposed arms 22 and 23, respectively, the said fingers being inturned, and beveled on their respective upper surfaces to form the cams 24 and 25. The detent I9 is adapted to be positioned within the recess H. The recess should be of such size that when the detent is inserted therein the fingers 20 and 2| will lie positioned in the T slot and arms 22 and 23, resting on the bottom of the recess I1, will be able to move out laterally a distance sufficient to permit the empty case to pass between the said fingers.

As has already been pointed out, a live cartridge is withdrawn from the belt by the extractor during the recoil of the gun and carried to a position immediately above the T slot. At the same time, the empty case is being withdrawn from the chamber by the T slot. As the bolt moves to the rear, the extractor cam forces the extractor downward, causing the cartridge to enter the T slot above the empty case held therein. Upon counter-recoil, the extractor is forced farther down, the live cartridge pressing upon the empty case. The empty case impinges upon the cams 24 and 25, forcing the arms 22 and 23 to move out laterally away from each other until the empty case, passing between the fingers 20 and 2!, is expelled from the T' slot, whereupon the arms- 22 and 23 are returned to their original positionby the released energy of the resilient arms, to act as a stop to position the live cartridge in the T slot so that it may enter the chamber of the gun.

It should be noted that the empty case is forced past the fingers 20 and 2| to make room for the new round only as the new round is moved into the T slot by the extractor. Since no new round is being moved into the T slot to eject it, the empty terminating adjacent said open end of said slot,

two spring arms, each said arm fitting and secured in a respective groove, each said arm having an end formed to extend into and obstruct a respective channel, whereby to engage the flange of a .cartridge and locate the same in predetermined position longitudinally of said slot, said ends being cammed outwardly on application of force to said cartridge to permit movement of the cartridgeout of said slot.

2. The combination with the reciprocating bolt of arapid fire gun, said bolt having a slot in its forward end, said slot being T-shaped in cross section to provide a pair of opposed undercut channels in which the flanged end of a cartridge is slidablyguided, a U-shaped retaining spring having its free ends laterally ofiset to form fingers, said spring being mounted on said bolt with each said finger extending into a respective channel to thereby engage and position a cartridge in predetermined position in said slot, said fingers being cammed out of said channels by a force applied to said cartridge in a direction parallel with said slot, to thereby permit said cartridge to be expelled therefrom.

3. In a gun having a reciprocating bolt, said bolt being formed at its forward end with spaced parallel confronting channels in which the flanged head of a cartridge is slidably guided, U-shaped spring means carried by said bolt and having its ends inwardly turned to form fingers, each finger yieldingly obstructing the lower end of a respective channel to engage and yieldingly locate the head of a cartridge in predetermined position in said channels.

CARL G. SWEBILIUS.

REFERENCES CITED The following references are of record'in the file of this patent:

UNITED STATES PATENTS Date 

